Merge pull request #11 from kbishop711/master

Implemented Revoke, and updated GetOrderByPartnerOrderID
Refactor response calls to remove duplicated logic
Merge pull request #12 from cloudkeep/refactor-response

Refactor response calls to remove duplicated logic
Enable Python 3.4 on Travis
Enable closing the session and usage as a context manager
Merge pull request #13 from cloudkeep/enable-py34

Enable Python 3.4 on Travis
Merge pull request #14 from cloudkeep/close-context-manager

Enable closing the session and usage as a context manager